* Extensive changes to permit symbols to contain any expression

	* Extensive changes to permit symbols to contain any expression
	type and to delay the computation of the expression until the
	value is actually needed.  This permits setting symbols to values
	calculated based on object code size.  Expressions were changed to
	no longer be in a section, to stop the overloading of segment and
	expression type that previously occurred.

	* as.c (big_section, pass1_section, diff_section, absent_section):
	Removed.
	(expr_section): Added (used for dummy symbols which hold
	intermediate expression values).
	(perform_an_assembly_pass): Create expr_section, do not create the
	sections now removed.
	* as.h (segT): Removed SEG_ABSENT, SEG_PASS1, SEG_BIG, and
	SEG_DIFFERENCE.  Added SEG_EXPR.
	(SEG_NORMAL): Corresponding changes.
	* subsegs.c (seg_name, subsegs_begin): Changed accordingly.
	* write.c (write_object_file): Ditto.
	* config/obj-aout.c (seg_N_TYPE): Ditto.
	* config/obj-bout.c (seg_N_TYPE): Ditto.
	* config/obj-coff.c (seg_N_TYPE): Ditto.
	* config/obj-coffbfd.c (seg_N_TYPE): Ditto.
	* config/obj-vms.c (seg_N_TYPE): Ditto.

	* expr.h (operatorT): Moved in from expr.c, added some values.
	(expressionS): Added X_op field, removed X_seg field; renamed
	X_subtract_symbol to X_op_symbol.
	* expr.c: Extensive changes to assign expression types rather than
	sections and to simplify the parsing.
	* write.c (fix_new_internal): New static function.
	(fix_new): Removed sub_symbol argument.
	(fix_new_exp): New function, takes expression argument.
	* write.h: Prototype changes for fix_new and fix_new_exp.
	* cond.c (s_if): Changed accordingly.
	* read.c (s_lsym, pseudo_set, emit_expr, parse_bitfield_cons,
	parse_repeat_cons, get_segmented_expression,
	get_known_segmented_expression, get_absolute_expression): Ditto.
	* symbols.c (resolve_symbol_value, S_GET_VALUE, S_SET_VALUE):
	Ditto.
	* write.c (write_object_file): Ditto.
	* config/obj-coff.c (obj_coff_def, obj_coff_val): Ditto.
	* config/obj-coffbfd.c (obj_coff_def, obj_coff_val,
	obj_coff_endef, yank_symbols): Ditto.
	* config/obj-elf.c (obj_elf_stab_generic, obj_elf_size): Ditto.
	* config/tc-a29k.c (md_assemble, parse_operand, machine_ip,
	print_insn, md_operand): Ditto.
	* config/tc-h8300.c (parse_exp, colonmod24, check_operand,
	do_a_fix_imm, build_bytes): Ditto.
	* config/tc-h8500.c (parse_exp, skip_colonthing, parse_reglist,
	get_specific, check, insert, md_convert_frag): Ditto.
	* config/tc-hppa.c (the_insn, fix_new_hppa, cons_fix_new_hppa,
	md_assemble, pa_ip, getExpression, getAbsoluteExpression,
	evaluateAbsolute, pa_build_unwind_subspace, pa_entry,
	process_exit): Ditto.
	* config/tc-hppa.h (STAB_FIXUP, is_DP_relative, is_PC_relative,
	is_complex): Ditto.
	* config/tc-i386.c (pe, md_assemble, i386_operand,
	md_estimate_size_before_relax, md_create_long_jump): Ditto.
	* config/tc-i860.c (md_assemble, getExpression, print_insn):
	Ditto.
	* config/tc-i960.c (parse_expr, subs, segs, md_convert_frag,
	get_cdisp, mem_fmt, parse_ldconst, relax_cobr, s_sysproc,
	i960_handle_align): Ditto.
	* config/tc-m68k.c (struct m68k_exp, struct m68k_it, seg, op,
	subs, add_fix, isvar, m68k_ip, md_assemble, md_convert_frag_1,
	md_estimate_size_before_relax, md_create_long_jump, get_num):
	Ditto.
	* config/tc-m88k.c (md_assemble, get_imm16, get_pcr,
	md_create_short_jump, md_create_long_jump): Ditto.
	* config/tc-mips.c (md_assemble, append_insn, gp_reference,
	macro_build, macro, my_getExpression): Ditto.  Also removed
	get_optional_absolute_expression; just use get_absolute_expression
	instead.
	* config/tc-ns32k.c (get_addr_mode, evaluate_expr, convert_iif,
	fix_new_ns32k, fix_new_ns32k_exp, cons_fix_new_ns32k): Ditto.
	* config/tc-ns32k.h (fix_new_ns32k prototype): Ditto.
	* config/tc-sh.c (parse_exp, check, insert, md_convert_frag):
	Ditto.
	* config/tc-sparc.c (md_assemble, sparc_ip, getExpression,
	print_insn): Ditto.
	* config/tc-tahoe.c (struct top, md_estimate_size_before_relax,
	tip_op, md_assemble): Ditto.
	* config/tc-vax.c (seg_of_operand, md_assemble,
	md_estimate_size_before_relax, md_create_long_jump): Ditto.
	* config/tc-z8k.c (parse_exp, check_operand, newfix): Ditto.